added files, terminal switch and scheduling not faulting

student-distrib/filesys.c

student-distrib/i8259.c

student-distrib/idt_asm.S

student-distrib/kernel.c

student-distrib/keyboard.c

student-distrib/lib.c

student-distrib/lib.h

student-distrib/paging.c

student-distrib/paging.h

student-distrib/pit.c

student-distrib/pit.h

student-distrib/proc.c

student-distrib/rtc.c

student-distrib/scheduler.c

student-distrib/scheduler.h

student-distrib/syscall.c

student-distrib/terminal.c

student-distrib/terminal.h

student-distrib/tests.c

student-distrib/types.h